AS Daily A Level Physics question

2026-06-29 OCR A High level GCSE physics Module 3.3 Work, energy and power — conservation of mechanical energy; work done by a constant force Module 1.1 Practical skills — stating and using assumptions (negligible losses)

In a lab, a friction pad exerts the same average retarding force each time a cart passes through it. Two identical carts start from rest at the top of smooth ramps of heights h and 2h, roll down, and then enter the pad, which brings each to rest. Ignore energy losses on the ramps. Which statement about the stopping distances inside the pad must be true?

A The cart from 2h has double the stopping distance of the cart from h. (correct)
B Both carts have the same stopping distance because the braking force is the same.
C The cart from 2h has about 1.4 times the stopping distance of the cart from h.
D The cart from 2h has four times the stopping distance of the cart from h.

Answer

The correct answer is A.

Correct: A — The cart from 2h has double the stopping distance of the cart from h. A This follows because the cart’s kinetic energy at the bottom equals mgh (or 2mgh), and with the same braking force the stopping distance is proportional to that energy, so doubling h doubles the distance. B This assumes equal force implies equal distance, but with a given force the distance depends on initial energy, which is larger from 2h. C This treats stopping distance as scaling with speed (v ∝ √h), but with a fixed force it scales with energy (∝ h), not directly with speed. D This incorrectly assumes doubling the height doubles the speed (it increases by √2), then overapplies the v² idea to get a factor of four.

Try today's guest Daily MCQ A Level Physics MCQ practice Problem-solving previews